Power converters are essential for many modern electronic devices. Among other capabilities, power converters can adjust voltage level downward (buck converter) or adjust voltage level upward (boost converter). Power converters may also convert from alternating current (AC) power to direct current (DC) power, or vice versa. Power converters are typically implemented using one or more switching devices, such as transistors, which are turned on and off to deliver power to the output of the converter. Power converters may also include one or more capacitors or inductors.
In some applications for power converters, the load current may vary significantly (e.g., over several orders of magnitude). For example, in today's microprocessor applications, when switching out of “sleep” mode, processors may activate a large number of dormant circuits, which results in a large step-change in load current (e.g., 150 A) within a relatively short period of time (e.g., a few hundred nanoseconds). For such applications with a very high slew rate (such as 1000 A/μs), it is desirable for the power converter to be able to rapidly respond in order to provide proper regulation. Previously developed designs for power converters use linear control. Such power converters with linear control are not able to timely respond to fast changes in load current (large step-change in load).